This invention relates to stab-type couplings or couplings in which assembly of a smooth wall tube to a coupling body is accomplished by pushing or thrusting the tube into the coupling body. Gripping of the tube surface and the resistance to attempted withdrawal is based on the "Chinese finger" principle. A segmented retaining collet cooperates with the tube such that the greater the pull-out force the more securely the tube becomes seated within the coupling.
Stab-type couplings have been known to the prior art for a considerable period of time. Such couplings are relatively easy to use in installation and require merely severing the end of the tube at right angles and chamfering of the tube end to facilitate insertion of the tube into the coupling body. As an example, prior art stab-type couplings have used both solid and split-type gripper rings, solid or split-type gripper washers and various spring-type elements.
One problem encountered by stab-type couplings in the prior art is the complexity of design which requires special machining of parts resulting in increased costs. A further problem encountered in the prior art has been the relatively complicated assembly procedure that must be practiced with certain designs.
With the foregoing in mind, it is an object of the present invention to provide a stab-type coupling which provides a simple reliable connection for on site installation of new pipe and tubing or repair of damaged pipe and tubing without the need for cathodic protection.